Example of level-η rotamers. (Color online) In figure a) we have all the Nη2 atoms in ARG. There are two very close rotamer states, which have been encircled. Some outliers have also been encircled. In figures b)-d) we show the subsets that correspond to loops, β-stranded and α-helical secondary structures, respectively. Comparison of the figures reveals that the two very close-by rotamers in a) correspond to loops and α-helices.